Yarn control means and method



y 1957 J. L. CHIVINGTON YARN CONTROL MEANS AND METHOD Filed Dec. 2'1,1954 HGiZL ATTORNEYS.

a v H w Zfidjidh Patented July 30, 1957 YARN CONTROL MEANS AND METHQDJohn L. Chivington, Signal Mountain, Tenn, assignor, by mesneassignments, to Patentex, Inn, New York, N. Y., a corporation of NewYork Application December 21, 1954, Serial No. 476,657

6 Claims. (Cl. 66-126) This invention relates to yarn control means andmethods. More specifically, it is concerned with a means for controllinghard twisted yarns which, when unrestrained, have the tendency to snarlincident to being delivered to the yarn manipulating instrumentalifiesof textile machines especially knitting machines used in the productionof articles such as so called stretch stockings and the like. Thissnarling characteristic is especially true of hard-twisted syntheticyarns of the thermoplastic polymer types such as nylon, Orlon and thelike.

The chief aim of my invention is to provide a simple and inexpensivemeans and method which can be relied upon to maintain hard twisted yarnsof the kind referred to taut, without imposition of undue tension,against snarling enroute, for example, to the needles of stockingknitting machines, notwithstanding dwells occasioned during the periodsof reversal in the traverse of the yarn carriers.

Other objects and attendant advantages will appear from the followingdetailed description of the attached drawings, wherein:

Fig. 1 is a fragmentary view, in transverse section of a straightknitting machine of the cotton type with a yarn control meansconveniently embodying my invention.

Fig. 2 is a fragmentary view of a portion of the organization shown inFig. 1 drawn to a larger scale.

Fig. 3 is a detail view in top plan looking as indicated by the angledarrows III-III in Fig. 2.

Figs. 4 and 5 are diagrammatic views showing the theory under which theyarn is controlled in accordance with my invention.

The knitting machine, herein illustrated in part for the purpose ofexemplifying my invention, is of the well known cotton type, such as iscommonly used in the production of flat fashioned stocking blanks,having a bar 1 with a complement of needles 2, cooperative sinkers 3, alinearly traversing yarn carrier 4, a humidifying box 5, for thestationarily-supported supply package P of the yarn Y to be knitted, ayarn moistening device 6 (which I use dry and only for the purpose of aguide), a yarn directing system including guide eyes 7, 8, 9, 10 and 11of which the guide 7 is fixed in the top of the box 5, a weighted takeup ring 12, and an intermittentlyactuated snapper 13 for checking theyarn during the intervals of reversal in the traverse of the carrier.

The control means which I have devised to prevent snarling of the yarnenroute to the carrier 4 from the supply package P over which the guide7 in the top of the humidifying box 5 is centered at a substantialelevation, includes a disk 15 which is fixedly supported in concentricrelation to the package atop the core C of the latter somewhat above thetop shoulder of the substantially cylindrically wound supply of the yarnon said core. As the yarn Y is drawn endwise from the package P throughthe guide 7, it is caused to gyrate about the disk 15 while infrictional contact with the edge of the disk. In actual practice, thedisk 15 is formed preferably from a dielectric plastic materialcommercially known as Lucite or Plexiglas on which, through rubbing edgecontact of the yarn therewith, a static charge is set up tending toattract and hold the yarn thereto. As a consequence of the angulardiversion of the yarn Y about the edge of the disk 15 as it passes fromthe package P to the guide eye 7 as shown in Figs. 1 and 2 andattraction thereof under the influence of the static charge, it iseffectively restrained against snarling even during the dwell periods ofthe carrier 4 at the ends of the traverse of the latter in oppositedirections. It is to be particularly noted that the edge of the disk 15is rounded, the curvature of the rounding being predetermined to providea definite area for contact by the yarn, this curvature being varied toprovide lesser or greater contact area for yarns having correspondinglesser or greater degrees of twist, or for yarns of the same degree oftwist but of different deniers. V v

Although, by preference, I employ a disk of dielectric material, a diskof metal or other conductive material may be used with interposition ofinsulation between it and the core of the yarn supply package.

The yarn control of my invention is believed to be operable under thefollowing theory:

The yarn and the disk being of diflferent materials and composed ofelectrons and protons, each of them is characterized by what may bedesignated as an electron pressure. When the yarn is drawn across theedge of disk, a potential, i. e., a contact potential, is establishedacross the boundary, the flow of electrons across the boundary tendingto neutralize such contact potential. Since the yarn and the disk aredielectrics or the latter is of metal or other conductive material witha support of insulation, separation after contact results in the twohaving equal electrostatic charges of opposite sign. When the yarn ofnylon or the like is drawn across the edge of the dielectric disk or aninsulated metal disk,

the contact potential causes transfer ofelectrons across the boundary,and a charge is built up on the disk and an equal charge of oppositesign is distributed along the yarn. If the disk is of a material higherin the elec trostatic series than the material of the yarn, the initialtransfer ofthe charge will result in a condition such as shown in Fig.4. However, as soon as the charge is built up on the disk, a phenomenonknown as dielectric polarization occurs. In the present instance, themole cules of the yarn are polarized so. that the potential due to thedoublets in the yarn tends to neutralize the contact potential andthereby reduce further transfer of electrons between the yarn and thedisk. Accordingly, the charge on the disk continues to accumulate orbuild up until the polarization potential approaches the same magnitudeas the contact potential. If the disk loses some of its charge by reasonof conduction through the moist atmosphere or its support, thepolarization potential is reduced proportionally, and the contactpotential immediately produces a flow of electrons across the boundaryand establishes a balance between the polarization potential, theconductive IR drop, and the contact potential. Hence, a condition ofequilibrium is maintained wherein the potential of the disk may beconsiderably below the contact potential due to the conductive losses asdiagrammatically shown in Fig. 5. Since opposite charges attract, thecharge on the disk will attract the opposite charge on the yarn, and thelatter be held against the edge of the disk by a force represented by F:kQE where F is the force (in dynes) normal to the surface, where k isthe dielectric'constant of the air, and where E is the electrostaticfield due to polarization of the yarn. It therefore follows that, as theyarn is drawn across the edge of the disk a frictional drag f results.This drag is represented by f=uF where u is the coefficient 1. Thecoefiicient of friction, which is determined by the nature of thematerials of the yarn and the disk and the smoothness of the disksurface.

2. The contact potential between the yarn and the disk, which isdetermined by the nature of the materials.

3. The conductive losses, which are primarily determined by' thehumidity of the atmosphere.

While, forthe purposes of exemplification herein, I have shown myinvention, in a form suitable for use in connection with a knittingmachine to produce blanks for'stockings of thestretch type, it is to beunderstood that my inventionis not to be considered as limited to suchapplication since, by suitable modifications within the scope of theappended claims, it is equally applicable to circular knitting machinesas well as to other kinds of textile machines as will be readilyunderstood.

Having thus described my invention, I claim:

1. Means for controlling hard twisted yarn of nylon or the likeenroute,from a substantially cylindric stationarily-supported supply package, tothe yarn manipulating instrumentalities of a knitting machine or othertextile machines for the formation of stretch fabrics, said meanscomprising a guide centered relative to the package at a substantialdistance therebeyond; an element of di-electric materialhavingcircularedge of larger diameter than that of the yarn Winding on the package,

, fixedly supported in axial relation to the package somewhat beyond thewinding atthe top, about which the yarn is gyrated while in frictionalrunning contact with the circular edge of the element and held theretounder static influence.

2. Yarn control means according to claim 1, wherein the edge of theelement is rounded at a curvature to predtermine a definite area forcontact by the yarn.

3. Means for controlling. hard twisted yarn of nylon or the like enrouteunder tension to the yarn manipulating instrumentalities of a knittingmachine or other textile machine for the production of stretch fabricsfrom a substantially-cylindric vertically-positionedstationarily-supported supply package, said means comprising a guidecentered over the package at a substantial distance thereabove; and anelement of di-electric material having a circular edge of largerdiameter than that of the winding on the package, fixedly supported inconcentric relation to the package on the end of the core of the lattersomewhat above the winding, about which element the 4 yarn is gyratedwhile in frictional contact with the edge of the element and heldthereto under static influence.

4. Yarn control means according to claim 3, wherein the edge of theelement is rounded at a curvature to predetermine a definite area forcontact by the yarn.

5. A method of producing articles such as stockings of the stretch typefrom hard twisted synthetic monofilament yarn of nylon or the like in aknitting machine having a complement of needles, a feed for feeding yarnto the needles, and guides for directing the yarn enroute from asubstantially cylindrical supply package to the feed, said methodcomprising the step of causing gyration of the yarn about afixedly-supported element of di-electric material having a circularedge, stationarily disposed coaxially in an interval between the supplypackage and one of the guides coaxially aligned therewith, so that theyarn is restrained against snarling through frictional engagement withthe edge of said element and held thereto under static influence.

6. A method of producing articles such as fashioned blanks for stockingsof the stretch variety from hard twisted monofilament yarn of nylon orthe like in a straight knitting machine of the cotton type having aneedle bar and cooperative sinkers, a traversing yarn carrierintermittently-actuated snapper means for checking the yarn during thereversal periods of the carrier, and a system of guides for directingyarn enroute from a stationarily supported substantially. cylindricalsupply package to the carrier, said method including the step of causingthe yarn to gyrate about a fixedly-positioned element of di-electricmaterial having. a circular edge, disposed coaxially in an intervalbetween the supply package and one of the guides axially alignedtherewith so that the yarn is restrained against snarling throughfrictional contact with the edge of said element and held thereto understatic influence.

References Cited in the file of this patent UNITED' STATES PATENTS1,209,179 Lipps Dec. 19, 1916 2,099,178 Snyder Nov. 16, 1937 2,514,582Johnson July 11, 1950 2,693,096 Quinn Nov. 2, 1954 OTHER REFERENCESNylon Technical Service, E. I. du Pont de Nemours and Co., Inc.,Wilmington 98, Del.; page 2-18.02.

Hosiery and Underwear Review, Dec. 1950, published by Knit GoodsPublishing Corp., New York 1, N; Y., page 124.

